Since hearing people comments to why Tobi could be Madara has made me warm up quite a bit to the idea of that
A little ticked off I just wrote crap loads just for the browser to cut off -.-
Anyway I am confused to how Madara knew Nagato, since Madara was around 100 years ago, I don't even think Jiraiya was alive when Madara was. So how could Madara know Nagato?
I am not sure whether Madara died or not. Maybe Madara died when he fought the 1st Hokage or he lived afterwards. Anyway remember Madara thought he was brought back by Nagato rebirth Jutsu? Do you also remember Tobi said Nagato rebirth Jutsu was for him when Nagato died?
I believe Madara and Tobi are now the same person, I believe Tobi is the split version of Madara. I do not know if anyone has noticed this. I had to re-check the manga to just refresh my memory. You only see Madara in this chapter with One Sharingan and when Tobi fought Konan his right eye closed when he used Izanagi, where his Main Sharingan has always been visible on his left side. Even now with the Rinnegan he keeps that left Sharingan. I believe that left Sharingan is Uchiha Madara's. I'm not sure how Madara managed to split himself in to two. Maybe Tobi was created by the help of Zetsu (Explains why his body is made up of Zetsu goo and is able to replace any limb). The split version is not the body etc, it solely the left eye of Uchiha Madara.
I do not believe Madara used Izanagi to save his life, it explains why he died. He used Izanagi to breathe life perhaps into the body Zetsu made and used his left eye to keep himself to live on. That could explain why Tobi has lived on for so long.
I am sorry if none of this makes sense, I already wrote all this out and it annoyed me to write it all again. If you don't understand some parts. Just say so I can explain it better.
To SUM it all up
Tobi is Madara, he has Madara left eye and Madara used Izanagi to keep that part of himself to live on through the Zetsu body, that is why the left eye perhaps didn't close,, Maybe the EMS gave him that ability to do this. It could explain why Tobi can not use EMS because he is not reunited with Madara.
Maybe it why Tobi had to agree to side with Kabuto because while Kabuto had control of Madara, he could never reunite with him.
Madara right eye is only visible
Tobi left eye was only visible (before the rinnegan)
I actually believe Madara and Tobi are the same person
I just don't know how Madara would know who Nagato was.